All Non‐Carbon B
<sub>3</sub>
NO
<sub>2</sub>
Exotic Heterocycles: Synthesis, Dynamics, and Catalysis
作者:Christopher R. Opie、Hidetoshi Noda、Masakatsu Shibasaki、Naoya Kumagai
DOI:10.1002/chem.201900715
日期:2019.3.27
The B3NO2 six‐membered heterocycle (1,3‐dioxa‐5‐aza‐2,4,6‐triborinane=DATB), comprising three different non‐carbon period 2 elements, has been recently demonstrated to be a powerful catalyst for dehydrative condensation of carboxylic acids and amines. The tedious synthesis of DATB, however, has significantly diminished its utility as a catalyst, and thus the inherent chemical properties of the ring
B 3 NO 2六元杂环(1,3-二氧杂-5-氮杂-2,4,6-三硼烷= DATB),由三种不同的非碳2期元素组成,最近被证明是羧酸脱水缩合的强大催化剂酸和胺。然而,繁琐的DATB合成大大降低了其作为催化剂的用途,因此,实际上仍未探索环系统的固有化学性质。在此公开了一种通用且简便的合成策略,该策略利用含嘧啶的支架可靠地安装硼原子,从而以模块化的方式由廉价材料制成了一系列Pym-DATB。可溶性Pym‐DATB衍生物的鉴定可用于研究B 3 NO 2的动力学性质环系统,根据介质的不同,显示出不同的开环和开环行为。易于获取的Pym‐DATB证明了其作为脱水酰胺化的有效催化剂的实用性,具有广泛的底物范围和官能团耐受性,为试剂驱动的酰胺化提供了一种通用且实用的催化替代方法。
A Versatile, Practical, and Inexpensive Reagent, Pyridine-3-carboxylic Anhydride (3-PCA), for Condensation Reactions
作者:Setsuo Funasaka、Teruaki Mukaiyama
DOI:10.1246/bcsj.81.148
日期:2008.1.15
A highly useful method for the preparation of carboxylic esters and carboxamides from various carboxylic acids was established by using a novel condensing reagent, pyridine-3-carboxylic anhydride (3-PCA), in the presence of 4-(dimethylamino)pyridine as an activator. The reactions of various carboxylic acids with nucleophiles, such as alcohols or amines, afforded the corresponding carboxylic acids or carboxamides in good to high yields under mild conditions by using simple experimental procedure. In addition, it was confirmed that this protocol was applicable to a gram-scale synthesis and the by-products, including pyridine-3-carboxylic acid and pyridine-3-carboxylate (or pyridine-3-carboxamide) produced in situ, were easily removed by using a simple aqueous workup.
Determination of absolute configuration of the derivative from 2-[4-(1-oxo-2-isoindolinyl)-phenyl]-propionic acid and R-(+)-1-phenylethylamine by 1H-NMR spectroscopy; use of shift reagent with diastereoisomeric amides
作者:Sergio De Munari、Giuseppe Marazzi、Angelo Forgione、Antonio Longo、Paolo Lombardi
DOI:10.1016/0040-4039(80)80022-0
日期:1980.1
The assignment of the S-(+), R-(−) absoluteconfiguration of Indoprofene, an analgesic and anti-inflammatory drug, has been made via an NMR configurational correlation of diastereoisomeric phenylethylamides with the aid of Eu(fod)3.